Correct-Answer to Question #20:
What was the Late Heavy Bombardment event?

Q.  What was the Late Heavy Bombardment event?

A.  It was a time in the past history of the Solar System when planets and moons had a lot more impacts from space.

Q.  When did it happen?
A.  About 4.1 to 3.8 billion years ago. The Solar System is about 4.7 billion years old, so the LHB started when the Solar System was about 600 million years old, and lasted for about 300 million years.

Q.  What caused the Late Heavy Bombardment?
A.  It was the time when the planets and other space stuff, previously in random orbits, were being normalized so their orbits lay closer to the equatorial plane of the Sun.

Q.  What caused this normalization?
A.  A gravitational effect called Equatorial Forcing.

Q.  Where is there more detail on this?
A.  See "P1: The Cosmic Smog model for solar system formation", at

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